Effects of Continuous vs Interval Aerobic Exercise on Cognitive and Vascular Function of Juvenile Rats

Abstract

Physical exercise is well‐known as an effective approach to improve cardiovascular function as a response to the cardiac overload and arterial shear stress that occurs during physical effort. In recent years physical exercise has been show to be effective to improve cognitive function, particularly memory, in individuals with neurodegenerative diseases but less is known about this effect in health individuals. Furthermore, an emerging issue on exercise science is to determine the optimal dose of exercise in favor of these benefits. The aim was to evaluate the effects of continuous versus interval aerobic exercise training on spatial learning and spatial memory, anxiety‐like behavior and vascular reactivity of juvenile rats. Male Sprague Dawley rats (10‐week‐old) were divided into three groups: sedentary (SD), continuous training (C‐tr), and interval training (I‐tr). The continuous (running at 60% during 40 minutes) and interval training (3 x 2 min of running at 70% with 4 min running at 35%) were performed 3 times/wk during 6 weeks. Elevated plus maze test (EPM) was carried out on Monday of the sixth week and Barnes maze task was initiated on Friday of the same week. Contraction response of carotid rings was determined by tension increase, from baseline, using cumulative concentration‐response curve to phenylephrine (Phe 1nM‐100μM) in intact rings. Endothelial function was measured either by cumulative concentration‐response curve to acetylcholine (ACh 10nM‐100μM) or measuring endothelium‐dependent increase in tension to L‐NAME (100 μM) in rings contracted by Phe (2 μM). Exercise regimens did not influence spatial learning and memory as primary escape latency was not modified. Open arm exploration of EPM was 42% higher in C‐tr indicating lower anxiety‐like behavior. Regarding vascular function, Phe potency was lower in C‐tr and maximal response was higher in I‐tr. However, both trained groups had L‐NAME‐induced tension increased by half compared to SD group. Neither maximal response nor potency of ACh was modified. In conclusion, spatial learning and spatial memory were not affected by both exercise training protocols. However, C‐tr produced better outcomes regarding anxiety‐like symptoms. Endothelial function was improved in a similar way, and then I‐tr can be considered time‐effective. These results could be useful to support the selection of exercise training protocol in animal model. It is of particular importance as physical exercise parameters (training regimen, effort intensity and duration, weekly frequency) produces specific behavioral and physiological adaptation.Support or Funding InformationFAPESP Grant # 2017/27042‐6